A suicide car bomber in Somalia's capital Mogadishu killed at least four people.

Security Ministry spokesman Mohamed Yusuf Osman told VOA security forces had surrounded the car in Waberi district near Mogadishu's international airport when an an al-Shabab militant detonated explosives in the vehicle.

He said the blast killed four civilians, as well as the suicide bomber. At least five other people were wounded.

Somali police officials said the bomber was targeting a convoy of Somali forces.

Residents said gunfire followed the explosion.

Al-Shabab group, linked to terrorist group al-Qaida, claimed responsibility for Sunday's attack. The Islamist group has recently escalated attacks on the Somali capital.

Sunday's blast comes days after several attacks on al-Shabab commanders. Early last week, a U.S. airstrike killed al-Shabab's intelligence chief, Abdishakur Tahlil. On Thursday, an al-Shabab commander, Ibrahim Filey, and three other militants were killed in a confrontation with Somali forces in the southern town of Kurtun Waarey.

Also last week, Somali authorities said al-Shabab fighters killed six Somali soldiers in Baidoa in an attack on a military checkpoint about 250 kilometers west of Mogadishu.